Aviation experts say bird-plane collisions happen daily. Nearly 200 people have been killed or injured since 1990 in accidents involving aircraft and wildlife. It is estimated that bird strikes cost military and commercial aviation over $2 billion each year due to damage and other costs. Most birds fly below 5,000 ft. However, bird strikes have occurred at 17,000 ft. and a few sightings have been made above 20,000 ft. In general, birds fly higher at night and during the spring and fall migration periods. They also fly higher in the presence of complete cloud cover.
Airports take a variety of measures to reduce bird populations near major airports. In a few cases, avian radars are used to detect flying birds near aircraft approach and departure paths. However, outside of these few major airports, no bird detection devices are currently available other than the pilot's see-and-avoid procedures.
Currently, most avian radars consist of modified marine radars using a long narrow horizontal antenna that is rotated in the horizontal plane to provide 360 degree azimuth coverage. These antennas provide narrow azimuth beamwidths and wide elevation beamwidths. Almost no target height information is provided due to the wide elevation beamwidths.
To obtain target height information, a second radar is sometimes added that uses a long narrow vertical antenna that is rotated in the vertical plane. Attempts are than made to correlate data from the vertical antenna radar with the two-dimensional (2D) data from the horizontal antenna radar to provide target height information.
Parabolic reflector antennas provide a narrow pencil beam in both azimuth and elevation in exchange for smaller volume coverage per 360 degree azimuth scan. The antenna elevation is slowly varied as the antenna rotates 360 in azimuth. Many azimuth rotations must be made to obtain a full elevation scan which takes considerable time. This results in a slow coverage volume update rate and poor bird tracking performance.
Military 3D phased array radars are available that can form multiple electronically pointed pencil beams that can provide rapid volume coverage update rates and excellent tracking. However, these radars are far too expensive for use as avian radars.
Current airport avian radars are used primarily for wildlife management and general alert purposes. That is, the radars help wildlife managers track bird movements and provide non-specific alerts to air traffic controllers when birds are in the vicinity of runways. However, without real-time precise positional and altitude information, current avian radars cannot be used to issue specific bird strike collision warnings or to alter air operations based on imminent bird collision threats.
Accordingly, it is the object of the present invention to disclose methods and apparatus which provide a new and improved low cost airport 3D avian radar that will provide precise real-time avian position and altitude information.